The present invention relates to an adsorbent which removes aldehyde as a component to be adsorbed for a long period, an adsorption device, other articles and an adsorbing method using the same. The invention can be applied for adsorbing the aldehyde efficiently, especially the aldehyde existing in a room of an automobile, a house or a residence.
As a method of removing components to be adsorbed in a gas, a sprinkler cleaning device is used at a large plant such as a sewage treatment plant and a trash burning plant in urban areas by using cleaning water which is prepared by dissolving an agent reactive with the component to be adsorbed. However, as a deodorizing method in a closed and narrow space such as a lavatory, a room in a house or an automobile, a conventional physical adsorbent such as an activated charcoal is used because it is impossible to install a large-scale sprinkler cleaning system therein.
On the other hand, it is confirmed that aldehydes such as formaldehyde, acetaldehyde and benzaldehyde and the like come from decomposed gases of fuels and oils, smoke of cigarettes, an adhesive used for laminating interior boards with interior members and heat insulating foamed resins, and remain in, for example, a room of an automobile. The aldehydes also come from heat insulating member, plywood, smoke of cigarettes, an adhesive and the like and remain in a house or a residence. Since these aldehydes are harmful, these components should be removed from the gas containing the aldehydes. As a method of removing the components to be adsorbed such as the aldehydes by adsorption, for example, an air cleaner which is filled with an activated charcoal adsorbent is known. However, the present inventors have found that little aldehyde was removed by the adsorbent such as an activated charcoal, although the components to be highly adsorbed can be removed to some extent. For example, since a physical adsorbent such as an activated charcoal removes a component to be adsorbed by adsorption-capturing in adsorption site, the physical adsorbent cannot adsorb the component any more when the adsorption site is once filled with the component. The physical adsorbent also adsorbs moisture(water) contained in a gas to be treated, thus does not serves as an adsorbent when the adsorption site is filled with the moisture. Therefore, the physical adsorbent tends to lose the adsorption performance in a short time due to the adsorption of the moisture which a gas contains in a considerable amount in a house or an automobile. In addition, the disadvantage of the physical adsorbent such as an activated charcoal is that the activated charcoal releases an adsorbate which the activated charcoal once adsorbed when the activated charcoal is used at the high temperature.
Japanese Examined Patent Publication No. 5-16299 discloses a crystalline aluminosilicate as a deodorant for an automobile and that H zeolite is preferably used as the aluminosilicate. H zeolite exhibits the desired performance as shown in examples of that specification when H zeolite is subjected to deodorizing the components to be adsorbed which is contained in a closed space like a sealed vessel. However, in a open space containing the components to be adsorbed, the adsorption ability is saturated soon due to the large amount of the components to be adsorbed, thus the deodorization effect is lost in a very short period such as several ten minutes.
The present invention have been accomplished to overcome the above problems. It is an object of the invention to develop and provide an adsorbent which adsorbs the aldehydes efficiently for a long period. It is another object to provide an adsorption device and other articles using the same. It is further another object to provide a method for adsorbing the aldehydes using the same.
According to the invention, the adsorbent contains a zeolite, wherein a component to be adsorbed is aldehyde; the zeolite contains NH4+ as ionic species; the zeolite has a crystal structure of ZSM-5 or ferrierite; the zeolite has the molar ratio of SiO2/Al2O3 from 30 to 190; and the zeolite retains a quarternary ammonium salt which adsorbs the aldehyde with the reaction of the aldehyde.
The adsorption device, other articles and an adsorbing method of the invention is characterized in using the above adsorbent.